The NYU Mass Spectrometry Core Facility for Neuroscience, the 100 Women in Hedge Funds Clinical Proteomics Facility and the NYU Protein Analysis Facility within the Kimmel Center for Molecular Biomedicine at the Skirball Institute at the NYU School of Medicine are dedicated to ensuring that biomedical scientists have access to cutting edge mass spectrometry technology to enable their research. We are requesting funds for a Thermo Electron LTQ-Orbitrap Velos mass spectrometer to make possible the accurate and sensitive detection, identification, characterization and relative quantitation of proteins and peptides involved in many important diseases for 11 NIH-funded major users and 5 minor users. In addition, the requested instrument would enable stable isotope labeling (SILAC) experiments for the study of intracellular signal transduction in neurons and other cells. These experiments would greatly increase our understanding of the causes and mechanisms of a number of neurodegenerative, developmental, infectious, and neuromuscular diseases and cancer.